Australian bushfire could double in size

PERTH - Residents of a West Australian town have been told to review their fire plans as a deliberately lit blaze continues to burn out of control in the state's south-west.

Six water bombers today joined more than 100 firefighters, who battled the fire overnight in steep terrain and gusty conditions.

Deep leaf litter and dry conditions are fuelling the fire south-east of Dwellingup, 97km southeast of Perth.

It has already destroyed more than 2,000 hectares and could double in size before it is contained, Department of Conservation and Land Management (CALM) spokesman Terry Maher warned.

"Fire suppression efforts will continue to have the support of six water bombers today, but it is expected that firefighting will be difficult and that the bushfire will continue to grow, and possibly double in size, before it is contained," he said.

Authorities doorknocked Dwellingup residents last night, warning them be ready to enact their fire plans.

And 1,500 bushwalkers and campers were evacuated from Lane Poole Reserve yesterday, some choosing to relocate temporarily to the Dwellingup town oval.

"Aerial surveillance of the reserve was undertaken last night by a WA Police helicopter to ensure that no campers remained in the area," Mr Maher said.

"Surveillance and road blocks will continue through today and tomorrow."

The bushfire has so far burned about 1750 hectares of Lane Poole Reserve and 250 hectares of a private blue-gum plantation, he said.

CALM hopes the fire can be contained before thunderstorms associated with former cyclone Daryl begin to affect the state's mid-west and south-west in the next few days.

"Some of the fuels in the path of the head fire have not been burnt for more than 20 years and this will lead to extensive spotting ahead of the main front of the fire," Mr Maher said.

"It will be hard slog using bulldozers to cut fire breaks along the flanks of the fire before the head fire can be cut off."

Motorists in the area have been warned about the smoke hazard.

The bushfire could also cause some haze in Perth.

- AAP